rewriteutil: add a precheck function to validate rewrite beforehand
For now this only checks for changeset mutability and this is only used by
'checkfold'. We'll expand the checking and usage as we go.
all: tutorials/tutorial.rst static/logo-evolve.ico
sphinx-build . ../html/
tutorials/tutorial.rst: tutorials/tutorial.t
python test2rst.py tutorials/
static/logo-evolve.ico: static/logo-evolve.svg
convert -resize 36x36 static/logo-evolve.svg static/logo-evolve.ico